The Japan international returned to Borussia Dortmund during the final days of the summer transfer period following a largely unsuccessful two-year spell at Manchester United.
BVB splashed out some eight million euros on the midfielder — only half of the price the Red Devils had paid for him in 2012.
Kagawa failed to fulfil his promise at Manchester United and hopes to rediscover his form at Borussia Dortmund.
While Kagawa’s first few weeks after his second debut at Dortmund have been far from successful for the club, the Japan international hinted at his potential in his first match against Freiburg and during last week’s 3-0 Champions League win at Anderlecht.
And former United coach Ferguson believes that Kagawa will rediscover his form, and become a key player at Dortmund again.
“I believe BVB and Kagawa did everything right. Shinji is back in surroundings where he feels like a fish in water,” Ferguson told Bild.
“And in [Jurgen] Klopp he has a coach who can provide him with the necessary confidence.”
Kagawa made an encouraging start at United in his first year, despite a lengthy injury lay-off, scoring six goals in 20 Premier League appearances.
However, he struggled to make an impact under the tutelage of Moyes last season and failed to find the back of the net in 18 games, 14 of them as a starter.
“I was very satisfied with Shinji. He settled well, and I had the feeling that he felt comfortable,” Ferguson said.
“Every manager has his own philosophy. When Moyes signed the Spanish superstar [Juan] Mata [during the 2013-2014 winter transfer period], Kagawa felt that he was no longer the first choice, and gave up a hope a bit.”